Cepstral Pitch Tracker

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*

    Permission is hereby granted, free of charge, to any person

    obtaining a copy of this software and associated documentation

    files (the "Software"), to deal in the Software without

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    modify, merge, publish, distribute, sublicense, and/or sell copies

    of the Software, and to permit persons to whom the Software is

    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be

    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR

    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

*/

#include "CepstrumPitchTracker.h"

#include <vector>

#include <algorithm>

#include <cstdio>

#include <cmath>

#include <complex>

using std::string;

CepstrumPitchTracker::CepstrumPitchTracker(float inputSampleRate) :

    Plugin(inputSampleRate),

    m_channels(0),

    m_stepSize(256),

    m_blockSize(1024),

    m_fmin(50),

    m_fmax(1000),

    m_histlen(1),

    m_vflen(3),

    m_binFrom(0),

    m_binTo(0),

    m_bins(0),

    m_history(0),

    m_prevpeak(0),

    m_prevprop(0)

{

}

CepstrumPitchTracker::~CepstrumPitchTracker()

{

    if (m_history) {

        for (int i = 0; i < m_histlen; ++i) {

            delete[] m_history[i];

        }

        delete[] m_history;

    }

}

string

CepstrumPitchTracker::getIdentifier() const

{

    return "cepstrum-pitch";

}

string

CepstrumPitchTracker::getName() const

{

    return "Cepstrum Pitch Tracker";

}

string

CepstrumPitchTracker::getDescription() const

{

    return "Estimate f0 of monophonic material using a cepstrum method.";

}

string

CepstrumPitchTracker::getMaker() const

{

    return "Chris Cannam";

}

int

CepstrumPitchTracker::getPluginVersion() const

{

    // Increment this each time you release a version that behaves

    // differently from the previous one

    return 1;

}

string

CepstrumPitchTracker::getCopyright() const

{

    return "Freely redistributable (BSD license)";

}

CepstrumPitchTracker::InputDomain

CepstrumPitchTracker::getInputDomain() const

{

    return FrequencyDomain;

}

size_t

CepstrumPitchTracker::getPreferredBlockSize() const

{

    return 1024;

}

size_t 

CepstrumPitchTracker::getPreferredStepSize() const

{

    return 256;

}

size_t

CepstrumPitchTracker::getMinChannelCount() const

{

    return 1;

}

size_t

CepstrumPitchTracker::getMaxChannelCount() const

{

    return 1;

}

CepstrumPitchTracker::ParameterList

CepstrumPitchTracker::getParameterDescriptors() const

{

    ParameterList list;

    return list;

}

float

CepstrumPitchTracker::getParameter(string identifier) const

{

    return 0.f;

}

void

CepstrumPitchTracker::setParameter(string identifier, float value) 

{

}

CepstrumPitchTracker::ProgramList

CepstrumPitchTracker::getPrograms() const

{

    ProgramList list;

    return list;

}

string

CepstrumPitchTracker::getCurrentProgram() const

{

    return ""; // no programs

}

void

CepstrumPitchTracker::selectProgram(string name)

{

}

CepstrumPitchTracker::OutputList

CepstrumPitchTracker::getOutputDescriptors() const

{

    OutputList outputs;

    int n = 0;

    OutputDescriptor d;

    d.identifier = "f0";

    d.name = "Estimated f0";

    d.description = "Estimated fundamental frequency";

    d.unit = "Hz";

    d.hasFixedBinCount = true;

    d.binCount = 1;

    d.hasKnownExtents = true;

    d.minValue = m_fmin;

    d.maxValue = m_fmax;

    d.isQuantized = false;

    d.sampleType = OutputDescriptor::FixedSampleRate;

    d.sampleRate = (m_inputSampleRate / m_stepSize);

    d.hasDuration = false;

    outputs.push_back(d);

    return outputs;

}

bool

CepstrumPitchTracker::initialise(size_t channels, size_t stepSize, size_t blockSize)

{

    if (channels < getMinChannelCount() ||

        channels > getMaxChannelCount()) return false;

//    std::cerr << "CepstrumPitchTracker::initialise: channels = " << channels

//              << ", stepSize = " << stepSize << ", blockSize = " << blockSize

//              << std::endl;

    m_channels = channels;

    m_stepSize = stepSize;

    m_blockSize = blockSize;

    m_binFrom = int(m_inputSampleRate / m_fmax);

    m_binTo = int(m_inputSampleRate / m_fmin); 

    if (m_binTo >= (int)m_blockSize / 2) {

        m_binTo = m_blockSize / 2 - 1;

    }

    m_bins = (m_binTo - m_binFrom) + 1;

    m_history = new double *[m_histlen];

    for (int i = 0; i < m_histlen; ++i) {

        m_history[i] = new double[m_bins];

    }

    reset();

    return true;

}

void

CepstrumPitchTracker::reset()

{

    for (int i = 0; i < m_histlen; ++i) {

        for (int j = 0; j < m_bins; ++j) {

            m_history[i][j] = 0.0;

        }

    }

}

void

CepstrumPitchTracker::filter(const double *cep, double *result)

{

    int hix = m_histlen - 1; // current history index

    // roll back the history

    if (m_histlen > 1) {

        double *oldest = m_history[0];

        for (int i = 1; i < m_histlen; ++i) {

            m_history[i-1] = m_history[i];

        }

        // and stick this back in the newest spot, to recycle

        m_history[hix] = oldest;

    }

    for (int i = 0; i < m_bins; ++i) {

        double v = 0;

        int n = 0;

        // average according to the vertical filter length

        for (int j = -m_vflen/2; j <= m_vflen/2; ++j) {

            int ix = i + m_binFrom + j;

            if (ix >= 0 && ix < m_blockSize) {

                v += cep[ix];

                ++n;

            }

        }

        m_history[hix][i] = v / n;

    }

    for (int i = 0; i < m_bins; ++i) {

        double mean = 0.0;

        for (int j = 0; j < m_histlen; ++j) {

            mean += m_history[j][i];

        }

        mean /= m_histlen;

        result[i] = mean;

    }

}

double

CepstrumPitchTracker::calculatePeakProportion(const double *data, double abstot, int n)

{

    double aroundPeak = data[n];

    double peakProportion = 0.0;

    int i = n - 1;

    while (i > 0 && data[i] <= data[i+1]) {

        aroundPeak += fabs(data[i]);

        --i;

    }

    i = n + 1;

    while (i < m_bins && data[i] <= data[i-1]) {

        aroundPeak += fabs(data[i]);

        ++i;

    }

    peakProportion = aroundPeak / abstot;

    return peakProportion;

}

bool

CepstrumPitchTracker::acceptPeak(int n, double peakProportion)

{

    bool accept = false;

    if (abs(n - m_prevpeak) < 10) { //!!! should depend on bin count

        accept = true;

    } else if (peakProportion > m_prevprop * 2) {

        accept = true;

    }

    return accept;

}

CepstrumPitchTracker::FeatureSet

CepstrumPitchTracker::process(const float *const *inputBuffers, Vamp::RealTime timestamp)

{

    FeatureSet fs;

    int bs = m_blockSize;

    int hs = m_blockSize/2 + 1;

    double *rawcep = new double[bs];

    double *io = new double[bs];

    double *logmag = new double[bs];

    // The "inverse symmetric" method. Seems to be the most reliable

    for (int i = 0; i < hs; ++i) {

        double power =

            inputBuffers[0][i*2  ] * inputBuffers[0][i*2  ] +

            inputBuffers[0][i*2+1] * inputBuffers[0][i*2+1];

        double mag = sqrt(power);

        double lm = log(mag + 0.00000001);

        logmag[i] = lm;

        if (i > 0) logmag[bs - i] = lm;

    }

    fft(bs, true, logmag, 0, rawcep, io);

    delete[] logmag;

    delete[] io;

    int n = m_bins;

    double *data = new double[n];

    filter(rawcep, data);

    delete[] rawcep;

    double abstot = 0.0;

    for (int i = 0; i < n; ++i) {

        abstot += fabs(data[i]);

    }

    double maxval = 0.0;

    int maxbin = -1;

    for (int i = 0; i < n; ++i) {

        if (data[i] > maxval) {

            maxval = data[i];

            maxbin = i;

        }

    }

    bool accepted = false;

    if (maxbin >= 0) {

        double pp = calculatePeakProportion(data, abstot, maxbin);

        if (acceptPeak(maxbin, pp)) {

            accepted = true;

        } else {

            // try a secondary peak

            maxval = 0.0;

            int secondbin = 0;

            for (int i = 1; i < n-1; ++i) {

                if (i != maxbin &&

                    data[i] > data[i-1] &&

                    data[i] > data[i+1] &&

                    data[i] > maxval) {

                    maxval = data[i];

                    secondbin = i;

                }

            }

            double spp = calculatePeakProportion(data, abstot, secondbin);

            if (acceptPeak(secondbin, spp)) {

                maxbin = secondbin;

                pp = spp;

                accepted = true;

            }

        }

        if (accepted) {

            m_prevpeak = maxbin;

            m_prevprop = pp;

        }

    }

//    std::cerr << "peakProportion = " << peakProportion << std::endl;

//    std::cerr << "peak = " << m_inputSampleRate / (maxbin + m_binFrom) << std::endl;

//    std::cerr << "bins = " << m_bins << std::endl;

//    if (peakProportion >= (0.00006 * m_bins)) {

    if (accepted) {

        Feature f;

        f.hasTimestamp = true;

        f.timestamp = timestamp;

        f.values.push_back(m_inputSampleRate / (maxbin + m_binFrom));

        fs[0].push_back(f);

    }

    delete[] data;

    return fs;

}

CepstrumPitchTracker::FeatureSet

CepstrumPitchTracker::getRemainingFeatures()

{

    FeatureSet fs;

    return fs;

}

void

CepstrumPitchTracker::fft(unsigned int n, bool inverse,

                    double *ri, double *ii, double *ro, double *io)

{

    if (!ri || !ro || !io) return;

    unsigned int bits;

    unsigned int i, j, k, m;

    unsigned int blockSize, blockEnd;

    double tr, ti;

    if (n < 2) return;

    if (n & (n-1)) return;

    double angle = 2.0 * M_PI;

    if (inverse) angle = -angle;

    for (i = 0; ; ++i) {

        if (n & (1 << i)) {

            bits = i;

            break;

        }

    }

    static unsigned int tableSize = 0;

    static int *table = 0;

    if (tableSize != n) {

        delete[] table;

        table = new int[n];

        for (i = 0; i < n; ++i) {

            m = i;

            for (j = k = 0; j < bits; ++j) {

                k = (k << 1) | (m & 1);

                m >>= 1;

            }

            table[i] = k;

        }

        tableSize = n;

    }

    if (ii) {

        for (i = 0; i < n; ++i) {

            ro[table[i]] = ri[i];

            io[table[i]] = ii[i];

        }

    } else {

        for (i = 0; i < n; ++i) {

            ro[table[i]] = ri[i];

            io[table[i]] = 0.0;

        }

    }

    blockEnd = 1;

    for (blockSize = 2; blockSize <= n; blockSize <<= 1) {

        double delta = angle / (double)blockSize;

        double sm2 = -sin(-2 * delta);

        double sm1 = -sin(-delta);

        double cm2 = cos(-2 * delta);

        double cm1 = cos(-delta);

        double w = 2 * cm1;

        double ar[3], ai[3];

        for (i = 0; i < n; i += blockSize) {

            ar[2] = cm2;

            ar[1] = cm1;

            ai[2] = sm2;

            ai[1] = sm1;

            for (j = i, m = 0; m < blockEnd; j++, m++) {

                ar[0] = w * ar[1] - ar[2];

                ar[2] = ar[1];

                ar[1] = ar[0];

                ai[0] = w * ai[1] - ai[2];

                ai[2] = ai[1];

                ai[1] = ai[0];

                k = j + blockEnd;

                tr = ar[0] * ro[k] - ai[0] * io[k];

                ti = ar[0] * io[k] + ai[0] * ro[k];

                ro[k] = ro[j] - tr;

                io[k] = io[j] - ti;

                ro[j] += tr;

                io[j] += ti;

            }

        }

        blockEnd = blockSize;

    }

}